The present invention relates to surgical implants, and more specifically to surgical plates.
Surgical plates, along with bone screws, are commonly used in the process of repairing broken bones in order to provide a distributed area of compression against the bones being clamped. Also, surgical plates are commonly used for spinal fusion or stabilization. Typically, a surgeon first places a surgical plate having screw holes onto a bone. He then drills screw holes into the bone with a drill. Then the surgeon will screw the plate onto the bone.
A problem that currently exists is that over time the screws may become loose and back out of the bone. This usually causes extreme discomfort to the patient and may lead to more serious health consequences.
What is needed is a surgical plate that is able to prevent screw backout.
The present invention provides a surgical plate and process for preventing screw backout of repaired bones. At least one pawl is provided on a surgical plate adjacent to a screw hole. A screw having a ratchet wheel is inserted through the hole and screwed into the bone. The pawl engages the ratchet wheel to prevent rotational movement of the screw to prevent the screw from backing out. In a preferred embodiment, a pawl plate comprising a base portion is rigidly connected to the surgical plate and a torsion bar is pivotally connected to the base portion. The pawl is positioned at the end of the torsion bar. In the preferred embodiments, several of these special screw holes with pawls, and several screws (each with a ratchet wheel) are used in bone repair.